I don't know what is going on in this case (and I don't know TIVO at all) but in the past I have worked on www sites that charge for media files (ie images and videos). I have used CGI so I could check that the user is logged in and allowed to download the file.

I don't really know why krkeegan is having trouble though if he is able to downlaod at 280kb/second unless that is not fast enough for the video stream. How fast does it download using PHP's fpassthrough function?